1. Field of the Invention
The subject invention is directed to plastic security envelopes, and more particularly, to a tamper-resistant envelope having two different adhesive closure seals associated therewith.
2. Description of the Related Art
Plastic security envelopes are well known in the art. They are commonly utilized to transport money, checks, bonds, stocks, food stamps, medical specimens, jewelry and other items of value. These envelopes must be constructed to remain closed during transport and handling, and resist tampering such that the contents are not compromised.
One problem that has arisen with respect to the adhesive materials utilized to seal plastic security envelopes is that the seals may be covertly opened after closure by lowering the temperature of the sealed region. This can be accomplished by spraying the envelope with a freon-type material or applying dry ice to the envelope. Once opened, the contents of the envelope can be accessed or removed, and the envelope can be subsequently resealed without any evidence of tampering.
Adhesive materials having adherent properties which are resistant to, or unaffected by low temperatures are also known and have been employed on security envelopes to prevent tampering. For example, U.S. Pat. No. 4,937,040 to Holcomb et al. discloses an adhesive closure system which includes means for forming indicia therein if the envelope is opened at temperatures substantially below room temperature. To fabricate the adhesive closure system, multiple layers of adhesive material are applied to the surfaces of the envelope. This fabrication process is time consuming and costly.
The subject invention provides an improved low-cost tamper-resistant security envelope which employs two different types of adhesive seals including one which is unaffected by low temperatures.